Electronic article surveillance (EAS) tags are commonly used to prevent shoplifting and other similar attempts to take goods outside a controlled area in a store. Usually, EAS tags are sensor tags, which are affixed to articles to be protected. The EAS tags are detected with a detection system, which is used at the exits of the store. If the article with the active EAS tag is carried out from the store, the detection system senses the tag and triggers an alarm. EAS tags are difficult to remove from the goods without a special release device, which is normally used by an authorised person, after the article has been bought or checked out.
To prevent an unauthorised removal of the EAS tag from an article, different mechanisms for locking an attaching element to the body of the EAS tag has been used. The attaching element for the EAS tag is conventionally a pin or a lanyard with a pin at the end. The locking mechanism utilises, for example, balls for locking the pin into the EAS tag body. This locking mechanism prevents the removal of the pin from the EAS tag body and can typically be opened with a strong magnet.
An electrical detection for sensing the unauthorised pin removal from the EAS tag body has been utilised with the locking mechanisms. A problem of these detection systems is the lack of reliability and the amount of mis-alarms. The assembly of the EAS tags with the known detection systems is difficult and not cost-effective.
There is, therefore, a need for a more reliable, simple and inexpensive solution for the pin detection of the EAS tag.